The homeownership rate fell slightly in the first quarter of 2016, dashing hopes that it had finally hit a bottom.

In the first three months of this year, the rate was at 63.5%, not seasonally adjusted. That is down from 63.8% in the fourth quarter of 2015, according to estimates published on Thursday by the Commerce Department. That puts it back near its 48-year low of 63.4% in the second quarter of 2015.

At the end of last year, economists had said the homeownership rate appeared to have stabilized and might begin to tick upward after falling for years following the housing crisis. When adjusting for seasonality, the homeownership rate in the first quarter also fell slightly to 63.6% from 63.7% in the fourth quarter of last year.

Some economists caution against reading too much into such a statistically small change in quarterly estimates. The fact that the homeownership rate is essentially flat is still good news, they said.

“We’re not seeing significant decreases like we were two, three, five years ago,” said Ralph McLaughlin, chief economist at real-estate information company Trulia.

The continued declines in the homeownership rate in part reflect a growing number of renter households. Some 363,000 new renter households were formed in the first quarter compared with the same time last year, about twice as many as the 177,000 new owner households.

That can drive down the percentage of households that own, while being potentially good news in the long-term because those new renter households are likely to eventually turn into owners.

Still, it also appears that factors such as rising home prices, student loans, delays in marriage and childbearing and uncertainty about buying a home as an investment are weighing on younger households and motivating them to rent instead of buy.

Another potentially worrying sign for the housing market: This was the second consecutive quarter when the number of new households formed was anemic, with the data showing just over 540,000 new households formed in total in the first quarter. In the third quarter of 2015, the number of renter households alone increased by 1.3 million.

Economists said recent signs of a U.S. economic slowdown could be dampening demand for people to strike out and form new households.

“It could also indicate that the expansionary period of economic growth is starting to flatten a bit,” Mr. McLaughlin said.